1. Field of the Invention
The present invention relates to the treatment of waste gases, particularly to a novel process for the removal of elemental mercury from such gases.
2. Background of the Invention
The 1990 Clean Air Act Amendments designate 189 substances as hazardous air pollutants also called "air toxics". Mercury has emerged as one of the air toxics of greatest concern. Mercury has been found in the stack emissions from U.S. power plants. Coal fired power plants account for the vast majority of the estimated total mercury emissions from all U.S. power plants. Mercury emitted from coal fired plants has been found in a variety of chemical forms, including elemental mercury and oxidized mercury compounds. Highly soluble mercuric compounds, such as mercuric chloride, are assumed to be readily removed in a wet scrubber system. However, elemental mercury, because of its very low solubility in water, has been shown not to be captured in a laboratory scale wet scrubber system. Therefore, in order to remove elemental mercury with a wet scrubber system, an additional method must be incorporated into the typical wet flue gas scrubbing process.